Purpose: 1. To identify the receptors on malaria parasites for red cell invasion and on infected red cells for adhesion to endothelium and to placenta. 2. To identify the red cell ligands for each parasite receptor. 3. To identify the minimal domain in the variant antigen for binding to placenta. 4. Test a region on the variant antigen for inducing protection against P. falciparum in Aotus monkeys and for overcoming variation. Accomplishments during the year: 1. The BAEBL ligand is blocked by purified glycophorin C, but not by N-glycanase treated glycophorin C. The N-glycan on glycophorin C differs for normal red cells compared to Gerbich red cells 2. The receptor domain of AMA1 for binding red cells has been identified as well as the Kx protein on the red cell for binding of AMA1. 3. The difference between Dd2 (no invasion of neuraminidase treated red cells) and Dd2/nm (invasion of neuraminidase treated red cells) has been identified.